Left: Cramming in the Butler Library, AJ stays on top of his studies. Right: AJ (holding mike) raps with his band, U-Kiss, in Seoul last October. Photo: Michael Sofronsky; Getty Images

AJ tosses the messenger bag over his shoulder, shoving his hands in his pockets, as a smirk forms from the corner of his mouth. The photographer’s camera clicks.

“Try to find the owl!” AJ says, nodding at Columbia University’s statue of the goddess Athena sitting behind him. “Finding it means you’ll do well in school.”

Two prospective students checking out the campus stop at the sight of the young man modeling for a photographer, his entourage waiting below. What is going on here? their faces say. Should we know who this is?

AJ goes unrecognized on campus because U-KISS is on few US students’ playlists.Photo: Michael Sofronski

AJ pays them no mind, instead tilting his head to the side to give another angle. He’s used to this, after all. No one in New York may recognize him, but back home in South Korea, he’s a star.

Meet AJ — born Kim Jaeseop — the 22-year-old member of Korean pop band U-KISS, who also happens to be a freshman at Columbia. Like Miley Cyrus’ Disney Channel character, Hannah Montana, AJ leads a double life — international heartthrob on one half of the Earth, psych major living in a dorm room on the other.

To date, his boy band has released five studio albums and 12 EPs that have produced 24 singles, totaling well over a quarter of a million records sold worldwide. U-KISS kicks off its first US mini-tour at the Best Buy Theater Thursday night.

Like virtually every boy band, each guy has a persona. AJ is the serious one, rapping about girls, girls and more girls. Fans even have a nickname for themselves — KissMes.

“In Korea and Japan, when the members of U-KISS go outside, they’re pretty much recognized. U-KISS is pretty famous,” he says. “[But] when I [came here for school], no one recognized me.”

Born and raised in Seoul, AJ got his start in the music industry at age 14. That’s when his older sister suggested to her friend, who was working for a company putting together a boy band, Paran, that AJ should audition — despite the fact that he couldn’t sing or dance.

“But my sister thought I looked like I should be in a band,” he says.

So did the company. AJ got the spot and left school in seventh grade to pursue an unlikely music career.

U-KISS (with a blond AJ at center) feel the love of their fans during the “Dream Concert 13″ event in Seoul last May.Photo: The Chosunilbo JNS/Getty Images

Upset that management didn’t want him to sing live because of his vocal cracks from puberty, AJ decided to sing into his mike during a dress rehearsal.

“My manager heard that and, in front of all of the producers, he said with this loud voice, ‘CAN YOU TURN OFF MIKE No. 5?’ ” recalls AJ. “I was really embarrassed, and I cried backstage.” That motivated him to take voice lessons.

After a few years with Paran, the group disbanded, and in 2011 AJ landed a spot with the higher profile boy band, U-KISS, an acronym for Ubiquitous Korean International Idol Super Star.

AJ’s current tour is produced by Mnet America, an English-language cable channel “for all things Asian cool,” which will feature them on the show “Headliners.” It finishes in time for him to start the semester at Columbia on Jan. 21.

Even at the height of his success, AJ was unhappy about having given up his schooling for his career. So he hired a tutor, studied relentlessly and earned his GED — and eventually got into one of the top colleges in the world.

“Although I did not receive a normal education like other students, I have been able to prove that I can compete with the best of them, taking control of my future,” he says.

His bandmates are supportive of the decision. One, Kevin Woo, even says he’d hire him as his therapist, should the whole psychology thing turn into a new career for him.

“There’s no reason for him not to be,” Woo says with a laugh. “He can really tell what someone is thinking. Roughly.”

But living AJ’s double life doesn’t come without its struggles.

“The pro is that I can experience the best of both worlds, but the con would be the confusion,” says AJ. “I am kind of confused on my identity. But since I chose this life, though it is difficult, I have to deal with it.”

AJ (crouching second from right in mustard-color jacket) knows all the band’s smart moves onstage in Seoul last March.Photo: Han Myung-Gu/WireImage

When AJ announced he was going to take time off to attend Columbia, the news spread across the K-pop blogs all the way over to America. Maybe life wouldn’t be so different over here.

“I knew that U-KISS wasn’t really a worldwide [phenomenon]. But on the other hand, I expected some students would notice me because there is a Columbia students’ blog, and they actually posted me on the page,” he says. “But since no one did notice me [once I got here], I was kind of disappointed.”

Eventually that first semester, AJ got a dose of his other life. “Since I missed Korean food desperately, I went down to Koreatown by myself, and one night after I had a dinner, there was one person declaring [to me] ‘I’m a KissMe!’” he says. “That was the first time someone in NY recognized me as a singer. I took a picture with her.”

Now AJ has found that keeping the worlds separate can be beneficial. Only a few of his friends in NY know about his secret. “I want them to know me [just] as a person,” he says.

In his first semester, AJ studied obsessively, sleeping only three to four hours a night, leaving virtually no time for play. This semester, now that he’s proven to himself that he won’t fail, he’s going to take it easier. He wants to join a fraternity, go see Broadway shows and experience NY’s great restaurants — with tequila, his favorite. Maybe he’ll even find a girlfriend.

“There is one dream that I want to do,” he says, searching for his words. “I want to have a campus couple.”